Talk:Three-mirror anastigmat

Korsch
There is an article (well, actually just a stub) by the lemma of Korsch telescope. Probably that stuff should be merged into the three-mirror-anastigmat-article. --BjKa (talk) 23:24, 17 May 2014 (UTC)

Off-axis three-mirror anastigmat
Hi,

the Paul and Korsch design necassarly put secondary in the optical path obstructing primary mirror, and usually requiring a spider (thus adding diffraction patterns from it) or optical flat (expensive, heavy, and reducing transmission). These problems are sometimes solved by using off axis designs, sometimes called tilted (TCT), like Schiefspiegler, Schupmann Medial Telescope (with Mangin mirror corrector), Schwarzschild-Chang type telescope (design from ~2016), Yolo, and few other designs are around. But I have no idea how they exactly compare to TMA (three-mirror anastigmat like Korsch), in terms of fully correcting spherical aberation, coma, and astigmatism, chromatic aberration, and flat field. Almost all of the mentioned above telescopes (with possibly exception of Schupmann), do not have chromatic aberration due to all reflecting design, and AFAIK no coma, due to non spherical and compensated mirrors. But I have no idea about the astigmatism. Would be nice to find good resources and fill it in. Some of the above designs are using three mirrors, so maybe it is related to this article. 81.6.34.246 (talk) PAGE ]]) 19:35, 12 March 2020 (UTC)
 * Hi, again me. I learned that some of NRO satellites, and some designs of WFIRST are using unobstructed three-mirror anastigmat, suggesting it is off-axis telescope. I couldn't really find exact diagrams of the optical assembly in any of the reports of the WFIRST, but it looks the design does exist. 81.6.34.246 (talk) 12:48, 12 February 2020 (UTC)
 * You can find some more detail on the WFIRST optical design here. There's nothing inherently different about an on-axis and an off-axis telescope design. If you used one-way mirrors and didn't have to worry about vignetting, a TMA could use three solid in-axis mirrors. However, in the real world, all on-axis TMAs take that idealized design and cut a hole out of the center of the mirrors to allow light to pass through. To make an off-axis TMA, you are essentially cutting out one side of the mirror instead of just a hole in the center. There are lots of other systems that have used this design, such as GIFTS and SBV. ---Ahecht ([[User talk:Ahecht|TALK